The Compendium of Caraka 4.8.19

4.8.19

tayoḥ karmaṇā vedoktena vivartanamupadiśyate prāgvyaktībhāvāt prayuktena samyak/ karmaṇāṃ hi deśakālasaṃpadupetānāṃ niyatamiṣṭaphalatvaṃ, tathetareṣāmitaratvam/

A transformation of the two [sexes] is taught through a rite prescribed in the Vedas, when properly applied prior to [the sex] becoming manifest; for rites endowed with the perfection of place and time invariably yield the desired fruit, and similarly other [rites yield] the contrary.